Answer
The word apostle at its root means “one who is sent.” Doctrine is simply teaching. So apostolic doctrine is teaching that comes to us through the apostles, those specifically chosen by Christ to carry His teachings to the world. The twelve disciples became the apostles (Mark 3:14) with the exception of Judas, who defected. He was replaced by Matthias in Acts 1:21–22. Matthias was a candidate for being an apostle because he had “been with us [the other apostles] the whole time the Lord Jesus was living among us, beginning from John’s baptism to the time when Jesus was taken up from us.” The Holy Spirit seemed to confirm this choice (Acts 1:23–26). Without negating the addition of Matthias to the group, God also chose Saul of Tarsus to be an apostle to carry the message to the Gentiles (Acts 9:15). We have access to the teachings of the apostles through the New Testament. For the most part, the New Testament was written by apostles or by those who were closely associated with the apostles.
The Gospel According to Matthew was written by the apostle Matthew, one of the original twelve disciples.
The Gospel According to Mark was written by Mark who is mentioned in Acts as an occasional ministry associate of Paul. Church history also tells us that Mark was an associate of Peter and that his gospel is based on Peter’s preaching.
The Gospel According to Luke and the Acts of the Apostles were written by Luke. Luke was a ministry partner of Paul and an eyewitness to many of the events in Acts. Although not an eyewitness to the life of Jesus, he conducted careful interviews that might have included interviews with the apostles (Luke 1:3). Much of the material in his gospel is similar to that in Mark and Matthew, so it is clear that he made use of apostolic sources.
The Gospel According to John, as well as the epistles of 1, 2, and 3 John and Revelation were written by the apostle John, one of the twelve disciples.
Romans, 1 and 2 Corinthians, Galatians, Ephesians, Philippians, Colossians, 1 and 2 Thessalonians, 1 and 2 Timothy, Titus, and Philemon were all written by the Paul the apostle.
James was written by the Lord’s half-brother James, who was the leader of the church in Jerusalem. Certainly, he would have been an eyewitness to much of the life of Jesus. He is never called an apostle, but he is called an elder and worked in tandem with the apostles. The apostle Paul in Galatians 2:9 calls James one of the “pillars of the church” along with the apostles Peter and John. It is interesting that James was not a believer until after the resurrection when Jesus appeared to him. First Corinthians 15:7 says that Jesus appeared to James and then “to all of the apostles,” which might indicate that James was considered to be an apostle at the time Paul was writing 1 Corinthians.
First and Second Peter were written by Peter the apostle.
Jude was written by another of the Lord’s half-brothers who also would have had much eyewitness experience to the life and teaching of Jesus. Like James, he was not a believer until after the resurrection.
Hebrews is the only book of the New Testament whose author is unknown. He was not an eyewitness to the Lord’s earthly ministry, but his work is based upon eyewitness testimony, as he says in Hebrews 2:3: “This salvation, which was first announced by the Lord, was confirmed to us by those who heard him.”
Apostolic doctrine is authoritative and vital to our understanding of what God has done for us. The writers of the New Testament refer to a settled body of doctrine that is often called “the faith” or “the gospel.” Jude 1:3 speaks of the “faith that was once for all entrusted to God’s holy people.” Paul strongly condemns people who would change or pervert the content of the gospel in Galatians 1:6–9: “I am astonished that you are so quickly deserting the one who called you to live in the grace of Christ and are turning to a different gospel—which is really no gospel at all. Evidently some people are throwing you into confusion and are trying to pervert the gospel of Christ. But even if we or an angel from heaven should preach a gospel other than the one we preached to you, let them be under God’s curse! As we have already said, so now I say again: If anybody is preaching to you a gospel other than what you accepted, let them be under God’s curse!”
In the list of gifts to the church, Paul lists apostleship as one of the foundational gifts (Ephesians 2:20). Once the foundation of the church had been laid and the teaching of the apostles had been recorded in Scripture, the role of apostle was no longer needed. There is still a need today for preachers, teachers, and missionaries to carry God’s Word (the apostolic doctrine) to the entire world (see Matthew 28:19–20; John 17:20).
Some churches today have the word apostolic in their name. For some, this may mean that they believe that the apostolic gift is at work in their church. If so, this would be a misunderstanding of the New Testament teaching on apostleship. For others, it may mean that they want to emphasize the apostolic doctrine as found in the New Testament. If that is what they truly do, then this is a good thing. One denomination, the Apostolic Church, says that they are following closely the teaching of the apostles but unfortunately believe that baptism by immersion is necessary for salvation and that salvation will be followed by sign gifts. While we see examples of the sign gifts being used in the book of Acts, it is not the teaching of the apostles that baptism is necessary for salvation or that every Christian will exhibit miraculous signs. In this case, although the name is “apostolic,” the teaching is not.
When the church began, Luke records, the early believers “devoted themselves to the apostles’ teaching” (Acts 2:42). That is, they were committed to learning and following apostolic doctrine. In this they were wise. If today’s church would be wise, they would also be devoted to the teaching of the earthly founders of the church, hand-picked by the Lord Himself.